Mitochondria (called “mitochondrion” in singular form) are places where oxidative phosphorylation (OXPHOS) and adenosine triphosphate (ATP) synthesis occur. Since ATP is used as a source of energy in a cell, the mitochondria are described as the powerhouse of the cell. In addition to generate energy required by the cell, the mitochondria also participate in cell division, cell signaling and apoptosis of the cell, and the mitochondria has the ability to control the cell-division cycle.